A multidisciplinary group has developed a seam-free, segmented polyurethane blood pump that has been extensively evaluated in a series of normal calves and has been shown to be capable of pumping 10 L/min and to be free of thromboembolic complications. This blood pump has been employed for cirulatory support in a small pilot study in calves with left ventricular failure and has been shown to be capable of complete support of the left side of the circulation. Studies to be performed over the next year include additional blood pumping from the left atrium to the aorta in normal calves, from the left atrium or left ventricle to the aorta in calves with induced left ventricular failure, and in continuing studies in patients with profound left ventricular failure post cardiac surgery or following myocardial infarct and shock. A low-speed, high torque, reversing brushless DC motor is being developed to actuate a pusher-plate and thus create pumping action in the blood pump of similar design. This implantable motor device will be implanted in the abdomen and will be evaluated for left ventricular apex to aortic pumping in calves. Studies performed under this grant will lead to a useful left ventricular assist device for short term circulatory support as well as an implantable unit for long-term permanent left ventricular support.